1. Field of the Invention
This invention provides a leather-like sheet material giving a feel of inclination in the direction of thickness, being soft but not so stretchy in the transverse direction, and having high peel strength, namely a leather-like sheet material having natural leather-like feelings as well as high mechanical properties rendering the same usable in making sports shoes.
2. Description of the Prior Art
For producing entangled bodies resulting from two or more webs or sheets made of different fibers and laid one over the other, followed by entanglement, and for producing leather-like sheet materials by impregnating them with a polymer elastomer, followed by coagulation, the following technologies are known in the art. Japanese Patent Publication JP Kokoku S48 (1973)-11925 describes a method of producing artificial leathers having, on one surface side, a nap consisting of ultrafine fiber bundles different form those constituting the nap on the other side, which method comprises laying two different fiber webs one over the other, impregnating the nonwoven fabric obtained after needle punching with a polymer elastomer and coagulating the elastomer. Japanese Patent Publication JP Kokoku S60 (1985)-43476 describes a method of producing suede-like sheet materials which comprises laying a flock composed of ultrafine fibers, 0.5 decitex or finer, on a substrate or ground fabric made of a woven or nonwoven fabric and causing a high-pressure liquid flow to spout against the resulting laminate from the flock side for entanglement and integration.
Japanese Patent Publication JP Kokoku S62(1987)-7309 describes a method which comprises laying a web made of ultrafine fibers spun by the melt blown method and a web made of short fibers of another kind one on the other, entangling the resulting laminate by means of a high-velocity liquid flow and filling the entanglement product with a polymer elastomer.
Japanese Patent Publication JP Kokoku S63(1988)-54832 describes a suede-like artificial leather comprising a structure consisting of ultrafine nonwoven fabric layers and a knitted fabric sandwiched between both nonwoven fabric layers, and a rubber-like elastomer distributed in the interspaces of that structure, wherein both nonwoven fabric layers differ in constituent fiber species and the fibers of both layers are intermingled with each other in the vicinity of the knitted fabric but substantially not intermingled with each other in the surface layer portions.
Laid-open Japanese Patent Application JP Kokai H11 (1999)-269774 proposes a structure structurally closer to natural leathers which is a laminate comprising fiber species differing in fineness and has a face on the finer fineness side.
Although leather-like sheet materials closer to natural leathers in which finer fibers are used on the grain side and thicker fibers on the opposite side, like the structure of natural leathers, have thus been proposed, leather-like sheet materials to be used in making shoes, in particular sports shoes, are required to have the feel and touch of natural leathers, be soft and resistant to transverse stretching in the state of shoes and show high peel strength in the bonded part between the instep and sole. However, no such leather-like sheet materials are yet available.